Technical Field
The present invention relates to a method of edging a spectacle lens, a spectacle lens edging system and a spectacle lens edging program for applying a beveling process to a spectacle lens.
Description of Related Art
A spectacle lens framed into a spectacle frame is formed by being subjected to an edging process applied to an uncut lens. An edging process includes “edging” for cutting and polishing the uncut lens so as to match a spectacle frame shape, and “beveling” for providing a bevel on an edged lens.
Such an edging process is performed based on frame shape data of a spectacle frame. Namely, the edging process and the beveling process are performed so as to match a groove shape of the spectacle frame specified by the frame shape data.
As described above, conventionally, the spectacle lens with a bevel is supplied by applying the edging process and the beveling process to the uncut lens, based on the frame shape data of the spectacle frame (for example, see patent document 1).    Patent document 1; U.S. Pat. No. 3,075,870
In recent years, the groove shape of the spectacle frame is not necessarily equalized, and for example various groove shapes (such as V-shaped groove and U-shaped groove) are distributed. Such a difference in the groove shape has a large influence on a measurement precision of the frame shape data of the spectacle frame. This is because if the groove shape is different, a positional relation between a measurement reference point (reference point uniquely determined from a position of a probe) estimated by a spectacle frame measuring machine, and an actually measured groove shape (particularly a groove tip point), even if the same spectacle frame measuring machine is used.
The same thing can be said for not only the difference in the groove shape, but also the difference in a type of the spectacle frame machine. It is general that the shape of the probe in the spectacle frame measuring machine is different depending on the type of the spectacle frame measuring machine, and which locus of the probe passing through a certain position is employed as the measurement reference point is also different depending on the type. Accordingly, the positional relation between the measurement reference point estimated by the spectacle frame measuring machine, and the actually measured groove shape (particularly the groove top point) is different if the spectacle frame measuring machine of a different type is used to perform measurement, even if the groove shape is the same.
Meanwhile, the same thing can be said for a lens edger that performs the edging process and the beveling process to the uncut lens. Namely, although various types exist as well regarding the lens edger, not only the formed bevel shape (particularly a top point angle of the bevel (120°, 118°, 110° . . . , etc.)) is different, but also the positional relation between a beveling instruction reference point (reference point uniquely determined by the type of the lens edger) for giving a beveling instruction, and the bevel shape (particularly the top point of the bevel) obtained by this beveling process is also different.
Under such a circumstance, the spectacle lens after beveling cannot be precisely fitted into the spectacle frame, depending on a combination of the groove shape of the spectacle lens, the type of the spectacle frame measuring machine to be used and the type of the lens edger to be used when the spectacle lens with a bevel is supplied, and therefore an edging size alignment by an actual body alignment is sometimes required. Such a case invites a situation that a complicated work of aligning the edging size by the actual body alignment is required, thereby also inviting a complicated work such as a product management and management of an edging step, because an actual body alignment process is interposed according to the above-mentioned combination. Further, there is absolutely neither flexibility nor versatility such as an interrupted edging is consecutively performed by a lens edger of other type in the middle of the edging step. When an edging size failure is generated under such a circumstance, it is extremely difficult to specify the cause thereof, and therefore it is also extremely difficult to cope with the size failure.
Therefore, an object of the present invention is to provide a method of edging a spectacle lens, a spectacle lens edging system and a spectacle lens edging program, capable of improving a fitting ratio into a spectacle frame of a spectacle lens after beveling, and realizing a supply of a beveled spectacle lens with a stable good quality.